In the field of food, methods of inerting are known which make it possible to package products that are sensitive to oxygen in a container with a low oxygen content.
In the case with liquid products intended to be packaged in a container with limited headspace (low volume of air between the opening of the container and the liquid contained), the method generally implemented industrially consists substantially in metering a drop of liquid nitrogen in the container on said headspace, then, when the air has been removed by the nitrogen passing to a gaseous state, in closing in a gas-tight manner the opening of the container.
The difficulty in implementing such a method resides substantially in the proper metering of the drop of nitrogen, as well as in the timing of the step of closing.
For example, an over-metering of the drop of nitrogen, or the closing of the container too early, can result in an internal pressure in the container that is too high, rendering fragile and even deteriorating the container. 
On the contrary, if the step of closing is too late, air will re-enter said headspace and the packaging will be defective.